Question 1

Leaching is most likely to affect the nutrients plants need in which soil horizon?

Accepted Answer

Leaching occurs in the topsoil horizon, as water moves through the soil and carries away soluble nutrients. This can result in nutrient depletion in the topsoil, making it more difficult for plants to access essential nutrients.

Question 2

Based on the fact that CO₂ is often limiting for photosynthesis,what might you conclude about the evolution of photosynthesis?

Accepted Answer

Photosynthesis likely evolved when CO2 concentrations were high, as early Earth had a much higher concentration of CO2, which would have driven the evolution of photosynthetic organisms to utilize this abundant resource.

Question 3

Water typically makes up about what percentage of a plant?

Accepted Answer

Water typically makes up about 90% of a plant. While some plants may have slightly different ratios, this is the general percentage for most plants.

Question 4

You find a sick plant in an arid environment.After studying it,you believe it is specifically defective in C₄ photosynthesis.What nutrient might this plant be lacking?

Accepted Answer

The answer of You find a sick plant in an...

Question 5

When certain bodies of water develop regions known as "dead zones" it often means that:

Accepted Answer

Dead zones occur when there is a significant decrease or depletion of oxygen in the surrounding water. This can happen when there is an excess of nutrients, usually nitrogen or phosphorus, which leads to an overgrowth of algae. When the algae die and decompose, bacteria consume the oxygen leading to a hypoxic or anoxic environment. This lack of oxygen can result in the death of fish and other aquatic organisms.

Question 6

When scientists are attempting to breed for increased ability of a plant to utilize carbon dioxide they must consider improvement of:

Accepted Answer

Bundle-sheath cells are involved in the C4 carbon fixation pathway, which is more efficient at utilizing carbon dioxide than the C3 pathway.

Question 7

Atmospheric levels of carbon dioxide have rapidly increased since the industrial revolution.Although bad for global warming,one positive outcome of this increase is that:

Accepted Answer

Studies have shown that certain crops such as tomatoes and cucumbers may experience enhanced growth rates in environments with higher levels of carbon dioxide. This effect is called the "CO2 fertilization effect" and can lead to increased yields of these crops. However, it is important to note that this positive outcome is outweighed by the negative effects of increased carbon dioxide on the climate and the environment.

Question 8

You are part of a team that discovers a new nitrogen-fixing bacteria in symbiosis with a plant.As you study this new bacteria,you discover that it is photosynthetic.This bacteria is likely to be:

Accepted Answer

Cyanobacteria are photosynthetic bacteria that can fix atmospheric nitrogen. They are commonly found in symbiosis with plants, and their ability to fix nitrogen provides an essential nutrient for plant growth. Therefore, it is likely that the new nitrogen-fixing bacteria discovered in symbiosis with a plant is cyanobacteria.

Question 9

Which activity may be helpful in reducing dependency on inorganic fertilizers?

Accepted Answer

Composting can be helpful in reducing dependency on inorganic fertilizers as it provides organic matter and nutrients to the soil, promoting the growth of plants. This can help to reduce the need for synthetic fertilizers. Nitrogen fixation is also a helpful process, but it requires specific bacteria and conditions, so it may not always be a practical option. Weathering, chlorosis, and leaching are not activities that directly reduce dependency on inorganic fertilizers.

Question 10

Which one of the following is NOT considered to be one of the macronutrients needed by plants?

Accepted Answer

Manganese is considered a micronutrient needed by plants, not a macronutrient. Macronutrients include nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur.

Question 11

Which of the following produce organic acids that may contribute to weathering of rocks?

Accepted Answer

Lichens produce organic acids that can contribute to weathering of rocks through chemical weathering.

Question 12

Macronutrients are defined as those elements:

Accepted Answer

Macronutrients are essential elements required by plants in relatively large amounts for growth and development. These include nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. The term "macro" refers to the fact that plants require these elements in larger quantities compared to micronutrients, which are required in smaller amounts.

Question 13

Potassium deficiency in plants is most common on light,sandy soils.This is likely because:

Accepted Answer

Sandy soils have larger pores and lower water holding capacity, which leads to faster drainage and leaching of nutrients, including potassium. This results in lower availability of potassium for plants and makes potassium deficiency more common in plants grown in sandy soils.

Question 14

Sunlight can actually be so intense that photosynthesis can be stopped.

Accepted Answer

While sunlight is necessary for photosynthesis, too much intensity can damage or even kill plant cells, stopping the process. This is particularly true for plants that live in very high light environments, such as desert plants.

Question 15

If you took a species of plant that normally grows on the forest floor and began to grow it in full sunlight,over generations,you may expect the plant's progeny to:

Accepted Answer

Plants that are grown in full sunlight will adapt to the change in light conditions over generations, and their progeny will have traits that are better suited for growth in full sunlight. Therefore, it is likely that the plant's progeny will grow mostly sun leaves that are better able to photosynthesize in full sunlight.

Question 16

Chlorosis in plants is a condition best explained by:

Accepted Answer

Chlorosis in plants refers to the yellowing of leaves due to the loss of chlorophyll, which is caused by a lack of certain minerals, most commonly iron or magnesium.

Question 17

Which of the following is the best answer for why plants require nitrogen?

Accepted Answer

Nitrogen is an essential component of amino acids and nucleotides, which are the building blocks of proteins and nucleic acids (such as DNA), respectively. Therefore, plants require nitrogen to synthesize these crucial molecules for growth and development.

Question 18

It is possible to manufacture a form of nitrogen that is useable by plants;however,the major drawback to this process is:

Accepted Answer

The major drawback to manufacturing a form of nitrogen that is useable by plants is the cost of converting nitrogen to a useable form. While it is possible to create a useable form of nitrogen, the energy and resources required to convert it are often expensive and can make it impractical for widespread use in agriculture.

Question 19

One of the ways agricultural production of such fruits as tomatoes or cucumbers can be increased significantly is to grow them in:

Accepted Answer

Growing fruits like tomatoes or cucumbers in greenhouses with extra carbon dioxide can significantly increase their agricultural production as it enhances photosynthesis and growth.

Question 20

A plant's ability to absorb carbon dioxide is reduced when:

Accepted Answer

Stomata are small pores on the surface of leaves that allow for gas exchange, including the uptake of carbon dioxide. If the stomata are closed, the plant's ability to absorb carbon dioxide is reduced.

Quiz 29: Flowering Plants: Nutrition and Transport